Yo aj, do you have a template or something for weather phenomena or something?
Nope. There's actually no templates for anything I write.
It basically goes like this:
1. Think up something cool
2. Write it up as if you were trying to explain it to someone. Or telling a story or something.
3.

4. Actually update The Highway.
If you want some examples of weather phenomena then look to other pieces of fiction or real life examples.
We basically have radiation storms that blow in from the West and just move all the way through the country. They happen sporadically (Read as: When the GM or computer decides it wants Armageddon to happen.), and normally take out a lot of people in the process. Everyone gets sick with rad poisoning as the radioactive fallout and rain seeps deep into the soil to the point that fallout shelters are about as bad if not worse then being above ground. And only the most secure places are safe.
The Great Wastes (IE: Big Ass Desert) gets Mad Max style sandstorms that have tornado and electricity traveling inside the belly of the storm.
You have all the normal crap like rain, hail, sleet, etc...
But if it is any help to you, anything that's added to anything nature related. Should in some way be harmful to people, as if Mother Nature herself was sick of humanities shit and wants them deader then Jimmy Hoffa going through a burger mincer. Including mutated fruit, veggies, and herbs.
They can be beneficial, but must have some secretive long term "bad" effect to go with it. Like: You have some fruit called Mutfruit. Its delicious, slightly radioactive, and has all your daily nutrients. Sadly its highly addicting to the point that people worship it as Mana from God. Its also acidic, put two and two together and you have a great lesson in moderation.